Halogen-terephthalic-hexahalides and process of preparing same



Patented July 19, 1932 UNITED STATES PATENT OFFICE HANS scnmnnnm, orFRANKFORT-ON7THE-MAIN-FEGHENHEIM, ennrrnnxnssrenon T0 GENERAL ANILINEwonxs'rno; or new YORK, n. AconroaA'rroN on "DELAWARE rHALOGEN-TEREPHTHALIC-HEXAHALIDES Ann raooEss orranranrne SAME NoDrawing. Application filed November 9, 1928, Serial No. 318,314, and inGermany November 11 1927.

Hal,

. GHa

wherein X means hydrogen or halogen, are

entirely halogenized in the side chains and the new hexahalogenocompounds of the formula:

C-Ha1a Hal,

C-Hah wherein X has the same signification, are obtained. Thehalogenation is advantageously carried out under exposure to light. Bysaponification in the usual manner the new hexahalogeno compounds "formmonoand dihalogenated derivatives of the terephthalic acid of theformula:

coon

wherein X has the aforesaid signification.

Whereas the monoand dihalogenated debeing by weight and all temperaturesin centigrade degrees, but I wish it to be understood that I am notlimited to the particular products nor reaction conditions mentionedtherein.

. Eaeample 1 I I 2 81 parts of '1.4E dimethyl-2-chlorobenzene aretreated at 150200 with chlorine, while exposed to an intense light,until no more chlorine is'absorbed. In this 'manner 406 parts ofchlorine aretaken up; When cool, the mass solidifies in a crystallizedform and can be used immediately 'for the further process. The newmono-chloro-terephthalic hexachlorideof the formula:

maybe isolated. therefrom in a purestate in the usual manner, itrepresents at ordinary temperature acrystallized substance, boilingunder atmospheric pressure above 300.

In order to saponify the monochloro-terephthalic hexachloride thusobtained, 347.5 parts of the raw product are introduced into 1200"parts'of sulfuric acid of -66-.B. At T0?80' a. violent reaction takesplace. The mixture is maintained at this temerature until the evolutionof hydrochloric acid ceases.

n'this manner 216 partsof hydrochloric acid are split OH". The mass isworked up .by

pouring it into ice. The 2-chloro-terephthalio acid thus isolatedcorresponds tothe formula:

COOH L OOH lfietedimethyl-iz.o-dichlorobenzene iis' treaed at about 180withchlorine, while exposed to light,funti1 no more chlorine i'sjtakenup.

The absorbed amount of chlorinecorre sponds approximately-to 6 atoms.The new "2.5-di- In-order to saponify the 2.5.-dichloro-. terephthalichexachloride 526 parts of the raw productaremixed at? 09-100 withl400parts.

of sulfuric acid of66 B, while well stirring. When the strong evolutionof hydroi 7 v vused' as starting material and the process is chloricacidihas ceased, the mass is poured on ice. The. precipitatedraw productis freed from .a-smallamount. ofv by-products by dissolving-it in acaustic soda solution andagain precipitatingthissolution with. an acid.-In this manner'th epure-2.5-dichloro terephthalic acid corresponding tothe. formula coon OOH

is obtained. It melts about 300. Its di methylester melts at 137 138,whereas 131 -I3'29 ismentioned as melting point in Berichte derdeutsclien chemischen Gesellschaft, .vol. 21', page'1960.

Example 3 Into/Z3. parts of mono-bromo-parmexylene,

bromine isi-introducedat 12015-0 :drop' by drop, while. stirring and:exposing toan intense. light, until no? more. bromineis: abserbed Inthismanner 160 parts of bromine.

are taken. up; At.ordinaryjtemperature the mass. soldifies inacrystallized: form.-. The new" mono-bromoterephthalic'i hexabromide 1of the. formula maybe isolated in a pure state in the usual manner. Itis at ordinary, temperature a crystallized-substance, boiling underatmospheric pressure above 300.

In order to saponifythe mono-bromo-terephthalic hexabromide,therawproductis introducedi' into an excess of sulfuric acid andthe-mixture. is-heated to 120130 until no more-.hydrobromic acid splitsofl. The mass -isworked up as described in the foregoing wherein X meanshydrogen, chlorine or broexamples. The 2-bron1o-terephthalic acid thusobtained corresponds to the formula:

(IJOOH doon. It. represents, whenrecrystallized fromalcohol, colorlesscrystalsmeltingabove 300, as described in literature (Berichte derdeutschen chem-ischen Gesellschaft, vol. 12, page 619) a Ewample 4 lVhen=2.51dibromo-1.4=dimethyl benzene is vtvherein X meanshydrogen,.chlorineorbromine. andY meanschlorine or bromine.v

2. A'process which comprises halogenating entirely in the side chains.by means of free members of the group consisting of chlorine andbromine while exposing to light a para- Xylene halogenated in thenucleus and corresponding to the general formula wherein X meanshydrogen, chlorine or bro- 'mine and Y meanschlorine or bromine.

3. As new products the halogen-terepl'i'thalic-hexahalides of theformula:

mine, Y and the Zs mean chlorine or bromine, which products are nearlycolorless liquids crystallizing at lower temperatures,

boiling under the ordinary pressure above 300 0., insoluble in water,soluble in organic solvents, capable of being saponifiecl to thecorresponding halogen-terephthalic acids.

4:. In the process for producing chloroderivatives of theterephthalicacid the step which comprises chlorinating entirely in theside chains by means of free chlorine a para- Xylene derivativechlorinated in the nucleus and corresponding to the general formula:

wherein X means chlorine or hydrogen. 7

ic-hexachlorides of the formula:

--Ols wherein X meanshydrogen or chlorine, which products are nearlycolorless liquids crystallizing at lower temperatures, boiling under theordinary pressure above 300 0., insoluble in water, soluble in organicsolvents, capable of being saponified to the correspondingchloro-terephthalic acids.

In testimony whereof, I alfix my signature.

I HANS SCHINDHELM.

